Catheters are commonly used in vascular interventional or diagnostic procedures. The catheter is threaded through the vasculature to a destination and treatment is applied at the destination. The treatment can take many forms, but a common treatment includes stent delivery wherein the stent is collapsible to a reduced profile delivery configuration for traversing the vasculature to the treatment site. Other treatments include the delivery of implantable devices that have a relatively large cross section, and may not be collapsible for convenient transluminal delivery via catheterization. Certain of these uncollapsible devices also may be constructed such that it is undesirable, or difficult, or expensive to provide a passageway through the device to accommodate guidewires or the like to assist in delivery. For example, it may be undesirable to design a battery for a leadless implantable pacemaker with a through-hole to accommodate a guidewire. Embodiments hereof relate to systems and methods for delivering a leadless pacing system, such as leadless medical implants within body tissue, such as tissue of the heart. A leadless medical implant that may be adapted for use in embodiments hereof is a leadless pacing system of the type described in U.S. Pat. No. 5,193,539 to Shulman et al. Generally, such a medical implant includes at least two electrodes and a capsule-shaped housing that hermetically encloses the pacing system's electrical components, including a wireless communication system and an internal power source. When implanted, the leadless pacing system is in electrical contact with heart tissue.
The medical implant described herein is sized to be tracked through the vasculature, i.e., through femoral, jugular, or subclavian blood vessels, within delivery systems hereof and may have a diameter or transverse dimension of up to 9 mm. Medical implants described herein may be delivered through the vasculature to be implanted at a septum of the heart or at the apex of the right ventricle. In other embodiments, medical implants described herein may be implanted within another heart chamber on either side of the heart. Although medical implants described herein are described as leadless pacing systems, in other embodiments hereof delivery and fixation systems and methods herein may be used to deliver and implant other medical devices that are configured to be secured within body tissue, such as a sensor device or another type of stimulator device, which may or may not be “leadless” or self-contained.
When using a catheter system to deliver devices that would otherwise be difficult to deliver, either due to crossing diameter or due to design characteristics, the open distal end of the catheter can either get caught on vascular tissue, or can inadvertently get directed into branch vessels, resulting in undesirably extending the time of treatment. It can be desirable to ease the passage through the vasculature by providing the catheter with a removable leader or a bumper tip. Therefore, it would be desirable to provide a catheter that overcomes the aforementioned and other disadvantages.